1. Field of the Invention
The present invention relates, generally, to a high-capacity anode material for rapidly chargeable and dischargeable lithium secondary batteries, and, more particularly, to an anode material composed of Li4Ti5O12 which is a transition metal compound having a nanocrystalline structure, and a method of preparing the anode material using a solvothermal synthesis process without performing additional heat treatment.
2. Background Art
Recently, with the rapid advancement of the electronic industry and the information and communications industries, including the mobile communications industry, electronic appliances have been required to become light, thin, short and small. According to these requirements, mobile IT products, such as notebook computers, mobile phones, personal digital assistants (PDAs), digital cameras, camcorders and the like, are widespread, and simultaneously high-performance, high-capacity and high-density small lithium ion batteries are being competitively developed.
Accordingly, various systems have been developed for lithium ion batteries employing graphite as an anode. However, the graphite anode has some disadvantages such as its initial loss of capacity, structural deformation and electrical disconnection.
To circumvent these problems, a class of anode materials called transition metal oxides (MoO2, SnO2, Ta2O5, NiO, CoO, CuO, FeO and Li4Ti5O12) have been investigated.
Among these materials, Li4Ti5O12 is has been acknowledged as an electrode material that has the advantages of a zero-strain insertion material, low cost and non-toxicity.
An exemplary conventional method of synthesizing Li4Ti5O12 is performed by employing a solid reaction process or a sol-gel process.
However, the conventional method of synthesizing Li4Ti5O12 using a solid reaction process can be problematic in that, since the reaction is conducted at a high temperature of 800˜1000° C., incidental expenses for increasing reaction temperature are increased, and the reaction products do not have a nanostructure. Further, in the conventional method of synthesizing Li4Ti5O12 using a sol-gel process the reaction must be conducted at a high temperature of 800° C. or more in order to obtain Li4Ti5O12□ having a spinel nanostructure, and so production costs are increased, and particles are grown by high-temperature heat treatment.
Accordingly, there remains a need in the art to provide a high-capacity anode material for rapidly chargeable and dischargeable lithium secondary batteries.
The above information disclosed in this the Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.